Vitamin D plays an integral role in bone metabolism and is one of the principal hormonal regulators of calcium and phosphorus absorption in the body. In 2011, the Endocrine Society defined Vitamin D deficiency as a 25 hydroxy vitamin D below 20 ng/ml and vitamin D insufficiency as a 25 hydroxy vitamin D of 21 ng/ml to 29 ng/ml.Without vitamin D, only 10 to 15% of dietary calcium and about 60% of phosphorus is absorbed.